Methods for producing a semifinished part for the manufacture of an optical fiber which is optimized in terms of bending

Abstract

Methods for producing a semifinished part for the manufacture of an optical fiber are disclosed. The methods are optimized in terms of bending. The methods include the steps of providing a shell tube with a shell refractive index which is lower in relation to the light-conducting core. Then, at least one protective, intermediate and/or barrier layer is applied to a radially outermost and/or innermost tube surface of the respective shell tube, wherein a build-up of light-conducting layers is realized on the inner side and/or the outer side of the shell tube. Finally, the shell tubes are joined by collapsing so as to form the semifinished part.

We claim: 
     
       1. A method for manufacturing a semi-finished optical product for a bend-optimized optical fiber, comprising:
 providing a cladding tube having an inner surface and an outer surface; 
 forming a protective layer on the cladding tube; 
 forming a light-guiding layer on the protective layer; and 
 collapsing the cladding tube onto a substrate to form the semi-finished optical product. 
 
     
     
       2. The method of  claim 1  further comprising:
 providing a plurality of cladding tubes; and 
 wherein the step of collapsing further comprises collapsing the plurality of cladding tubes onto the substrate. 
 
     
     
       3. The method of  claim 1  wherein the cladding tube is a fluorine-doped quartz glass tube. 
     
     
       4. The method of  claim 1  wherein the step of forming the light-guiding layer further comprises depositing the light-guiding layer using a process selected from the group consisting of CVD, PIVD, OVD, flame pyrolysis or combinations thereof. 
     
     
       5. The method of  claim 1  wherein the cladding tube has a melting point and wherein the protective layer is formed of quartz glass having a higher melting point than the melting point of the cladding tube. 
     
     
       6. The method of  claim 1  wherein the protective layer operates as a diffusion barrier to volatile glass compounds. 
     
     
       7. The method of  claim 1  wherein the protective layer is formed of at least one transition glass having a chemical composition tuned to minimize effects of differences between the semi-finished product and a substrate. 
     
     
       8. The method of  claim 1  further comprising forming a second protective layer on the light-guiding layer. 
     
     
       9. The method of  claim 1  further comprising controlling pressure on the inner and outer surfaces of the cladding tube. 
     
     
       10. The method of  claim 1  further comprising mechanical processing the semi-finished product to form a polygonal rod. 
     
     
       11. The method of  claim 1  further comprising collapsing a second cladding tube onto the semi-finished product, wherein the semi-finished product has a first chemical composition profile and wherein the second cladding tube has a second chemical composition profile, and wherein the first chemical composition profile and second chemical composition profile form, when combined, a structured profile, the structured profile being one selected from the group consisting of a constant profile, a linear profile, and a gradual profile. 
     
     
       12. The method of  claim 1  further comprising performing an outer deposition on the cladding tube. 
     
     
       13. The method of  claim 1  further comprising removing a part of the protective layer. 
     
     
       14. The method of  claim 1  further comprising surface treating the cladding tube. 
     
     
       15. The method of  claim 1  wherein the protective layer is formed on the inner surface of the cladding tube. 
     
     
       16. The method of  claim 1  wherein the protective layer is formed on the outer surface of the cladding tube. 
     
     
       17. The method of  claim 1  wherein the collapsing step further comprises partially collapsing the cladding tube.